This invention relates to a flow switch assembly for fluid flow switch monitoring devices, and more generally, the invention relates to a monitor device for monitoring fluid flow (both liquids and gases) in piping in which device a vane is to be inserted in the fluid flow for monitoring purposes and is moved by the force of the fluid flow, with the resulting motion being magnetically transformed into an electrical signal; in accordance with the invention, the electrical signal is provided by a novel switch assembly that includes an elongate housing formed from a suitable plastic non-magnetic material in which a reed switch is hermetically sealed in electrical circuit arrangement with lead wires having exteriorly exposed ends for connection in electrical circuiting of a variety of types, with the switch assembly being in field adjustable with respect to the monitoring device sensing body whereby the monitor assembly as a whole can be set so that the electrical switching provided is either Normally Closed (NC) or Normally Open (NO), with the switch assembly housing including both flanging and indicia for positively setting same relative to the monitoring device sensing body precisely at such Normally Open or Normally Closed positions.
Fluid flow monitors are commonly employed for application to piping for monitoring the conveying liquids and gases to equipment operated thereby. An example is the PSR Flowmonitor (See U.S. Pat. No. 4,828,092, granted Aug. 2, 1989) offered by the German firm known in the industry as Kobold, which German firm has what apparently is an American subsidiary, Kobold Instruments, Inc., of Pittsburg, Pa. Units of this type involve an elongate sensing body which houses a spring biased rocking vane assembly (called a "paddle"), which sensing body in use is suitably connected to the piping so that the vane portion (of the rockable vane assembly carried thereby) that projects from the open end of the elongate sensing body is disposed within the path of movement of the piping flowing fluid medium, with the vane assembly swinging about a center to move a switch activating magnet carried by such vane assembly within its sensing body; the portion of the sensing body exterior of the piping has a closed end exterior of the piping, adjacent the movement path of the magnet, in which is adjustably mounted a switch assembly of the conventional reed type that includes a elongatge plastic housing that mounts in hermetically sealed relation the reed switch involved in electrical circuit arrangement with lead wires that have externally disposed ends for incorporation in electrical circuiting of a type where an electrical switch function is required once a specific fluid flow is achieved. The PSR device can be set to operate as either a Normally Open (NO) or a Normally Closed (NC) switch function, by moving the reed switch housing, which thus provides adjustable "switch point".
Applicant has found in testing the Kobold PSR Unit has found that while such unit is adjustably arranged to nominally provide adjustable "switch point", the only indication for such adjustment that is available for such unit is in the form of a pair of small arrows applied to the exterior of the switch assembly housing, each indicating a Normally Open or Normally Closed switch function location of the switch assembly housing with respect to the monitor sensing body; Applicant has found, in this connection, that the arrow arrangement involved in connection with the Kobold PSR Unit does not provide the preciseness needed for this type of instrument, considering, for example, the off-hand manner in which, as a practical matter, instruments of this type are often in field set by those not really skilled in this art. Thus, the small arrows provided on such Kobold monitors leave room for individual interpretation and possible location error as there is no positive physical indication that the reed switch assembly has been located accurately to function as desired.
Accordingly, a principal object of the present invention is to provide a fluid flow switch monitoring assembly of the type indicated wherein the reed switch assembly, as mounted for adjustment laterally of the instrument sensing body, provides a positive physical indication that such switch assembly is properly located with respect to the instrument sensing body to provide the switch function desired.
A further object of the invention is to provide a fluid flow switch monitoring assembly of the type indicated wherein the reed switch assembly is formed to provide stops that engage the instrument's sensing body to provide a positive physical indication that the switch assembly is properly located with respect to the instrument's sensing body to provide the switch function desired.
Another important object of the invention is to provide a fluid flow switch monitoring assembly of the type indicated wherein the switch assembly is of the reed switch type, and the reed switch itself is precisely located within the switch assembly at the desired position for providing the Normally Closed (NC) switch function, and the switch assembly exterior is formed with projecting flanges that act as stops that on adjustment engage the instrument sensing body to provide a positive physical indication that the switch assembly of the present invention is properly located with respect to the instrument's sensing body to provide the switch function desired.
Another important object of the invention is to provide a fluid flow monitor of the type indicated wherein the reed switch that is employed in connection with the switch assembly is on the side of the switch assembly that is to be closest to the level of movement of the unit sensing body magnet, with the opposing side of such switch assembly being provided with indicia for positively indicating the position of the switch assembly relative to the unit sensing body for its Normally Closed (NC) switching function, or its Normally Open (NO) switching function, as are respectively provided by the indicated stop flanges.
Another important object of the invention is to provide a generally improved fluid flow switch monitoring assembly of the type indicated, which is surprisingly compact, solidly built, and leakproof as to the flow sensing body and switch assembly housing, and that is arranged to be in field calibrated to trigger on rising or falling flow rates (at the option of the installer), that is inexpensive of manufacture, that is easily calibrated and maintained, that is designed for long term trouble free service in critical operations, and is readily removed for inspection or replacement without shutting down the pipeline in which it is mounted.
Further in accordance with the invention, another important object is the provision of a novel but simple method of positively adjusting and setting at the desired switch point the unit switch assembly with regard to its sensing body.
In accordance with the present invention, a fluid flow switch monitoring device is provided, for application to piping for conveying liquids and gases to equipment operated thereby, comprising a sensing body to which is adjustably applied a fluid flow switch monitoring assembly that is arranged in accordance with the present invention. The monitoring device sensing body is formed from a non-magnetic material, such as brass, to define a bore or cavity extending longitudinally thereof that is open at one end thereof and is closed at the other end thereof, with the monitoring device sensing body cross mounting at its closed end an elongate off-on switch assembly for adjustment movement thereof laterally of the unit's sensing body, and with the sensing body having pivotally mounted within its bore or cavity, for pivotal movement in coplanar relation to the direction of fluid flow through the piping, a swing lever control device in the form of a vane assembly that includes at one end of same a vane projecting from the sensing body open and a permanent magnet adjacent to the other end that is disposed to the unit's sensing body closed end for effecting by magnetic action the activation of the switch device, with the basic unit including spring means mounted within the unit's sensing body for resiliently opposing such pivotal action, and with the basic unit involved including means for clamping the unit's switch device into fixed position relation with respect to the unit sensing body; pursuant to the present inventio, the unit switch assembly comprises an elongate housing formed from a suitable plastic non-magnetic material, that is shaped to define an elongate bore intermediate the ends of such housing, with a commercially available reed switch being potably mounted in the switch assembly housing bore in electrical circuit arrangement with lead wires extending from one end of the switch assembly housing, with the reed switch itself being disposed on the side of the switch housing that has a level which is closest to the path of movement of the basic unit magnet on pivotal movement of the vane assembly forming the unit lever control device (such side of the switch assembly housing hereinafter being referred to as the "switch side" ); with the switch assembly housing defining first and second stop means disposed one on either side of the basic unit sensing body for engagement with the basic unit sensing body when the basic unit's switch assembly is to be positioned to provide the normal closed (NC) or Normally Open (NO) functions of the reed switch (that is mounted within the switch assembly housing), with the positioning of the indicated reed switch within the switch assembly housing being such that the reed switch is disposed longitudinally of said housing to have its Normally Closed (NC) function when the switch assembly housing first mentioned stop means physically engages the unit sensing body, and with the switch assembly housing having the side of same that is opposite of its said switch side, bearing indicia indicating such Normally Closed (NC) and Normally Open (NO) functions and corresponding to the location of said first and second stop means. Such indicia is applied to an elongate label attached to the side of the switch assembly housing that is oppposite of its "switch side", for serving to indicate when the switch assembly is disposed with respect to the unit sensing body to be positioned at one of the aformentioned switch function providing positions; the unit sensing body at its closed end is slotted thereacross in parallelism with the direction of the fluid flow that is to be monitored for slidably receiving the switch assembly housing, with the "switch side" of said switch assembly housing being disposed in the indicated slot at said critical level. The fluid flow switch monitoring device of the present invention also includes a cap and a set of screw elements for clamping the switch assembly housing at the position relative to the unit sensing body that will provide the switch function desired (which is thus an option of the installer of the basic sensing device involved).